Synthesis of silver nanoparticles mediated by endophytic fungi associated with orchids and its antibacterial activity

In this study, 13 endophytic fungi strains were isolated from orchids, Dendrobium nobile, Dendrobium hibiki, and Oncidium altissimum. Two strains namely KDH5 and VDN3B were reported for the synthesis of SNPs by using 1 mM and 10 mM of silver nitrate solutions respectively. The present of SNOs was observed in wavelength ranging from 400 nm to 450 nm corresponding to the plasmon absorbance of SNPs. By applying various volume ratio of silver nitrate solution to fungal extracellular metabolites filtrate (FEMF), the UV-Vis spectrum showed an increasing trend of absorption intensity indicated that the concentration of SNPs synthesized is volume ratio-dependent. Scanning Electron microscopy image showed various diameter of SNPs present and energy dispersive X-ray spectroscopy (EDX) quantified the surface composition containing of 41.62 weight percentage of silver element. The antibacterial efficacy of synthesized SNPs was evaluated by Kirby-Bauer and time-dependent growth inhibition assays against several selected pathogenic bacteria including Staphylococcus aureus, Micrococcus luteus, Salmonella Typhi, Enterobacter aerogenes, Serratia marcescens and Escherichia coli. SNPs synthesized by FEMF from KHD5 and VDN3B showed highest effectiveness against E. coli, M. luteus and E. aerogenes at higher volume ratio respectively. Very interestingly, molecular identification proved that KDH5 and VDN3B as the strain of Podosordaria muli and Xylaria feejeensis which both were isolated from Dendr...
Source: Materials Today: Proceedings - Category: Materials Science Source Type: research